A communications network monitoring system is an important system which allows an operator to perform active monitoring and management. In a working process of the communications network monitoring system, various types of signaling and media data of a communications network are collected in a manner which does not affect network operation, where the manner includes high resistance cross-connection, port mirroring, splitting by an optical splitter; the collected signaling and media data is then sent to a data center; the data center performs decoding, association, call/session detail record (CDR)/transaction detail record (TDR) integration on the signaling and media data, to reproduce a whole service process, so as to collect statistics on all types of indexes about a network, a user, and a service. In this way, network maintenance personnel master and analyze network and service operation situations, market management personnel master and analyze user behaviors and service usage, and managerial personnel obtain a quantitative basis supporting decision-making. Using a voice service as an example, a call/session between users generally appears as a control stream on a control plane, and appears as a media stream on a user plane of a communications network, where both the control stream and the media stream are relayed and mediated by a series of network elements, and the network element may be a mobile switching center server (MSC), a media gateway (MGW), or the like. The communications network monitoring system collects various types of signaling and media data on a communications link between network elements; therefore, from the perspective of a call/session between users, the collected signaling and media data belongs to a single interface between network elements and are segmented, and the communications network monitoring system must associate the collected signaling and media data of each single interface, so as to obtain end-to-end call/session information. This process performed by the communications network monitoring system is referred to as multi-protocol multi-interface association. The communications network monitoring system can evaluate and analyze a communications network from the perspective of a whole network, a user, and a service only after completing the foregoing process.
In the prior art, the communications network monitoring system performs multi-protocol multi-interface association on a call/session based on an assumption that, for a same call/session, calling and called subscriber numbers collected on interfaces at both sides of a network element are the same. Calling and called subscriber numbers carried in collected call control signaling are used as an association basis, and the communications network monitoring system may associate, by comparing whether the calling and called subscriber numbers carried in the call control signaling collected on the interface at two sides of the network element are the same, single interfaces belonging to a same call/session.
However, in the foregoing method, because of demands for various types of services and routing based on a subscriber number, when mediating a call/session, a network element in a communications network often regulates and changes calling and called subscriber numbers; therefore, if association is performed according to subscriber numbers, accuracy of multi-protocol multi-interface association is affected, thereby seriously affecting reliability of the communications network monitoring system.